Two Stage Methods for Processing Adhesives and Related Compositions

• US 20190359866A1
• Filed: 08/05/2019
• Published: 11/28/2019
• Est. Priority Date: 02/19/2016
• Status: Active Grant

• Current Assignee: Avery Dennison Corporation
• Original Assignee: Avery Dennison Corporation
• Inventors: BARTHOLOMEW, Eric L., BOTTORF, William L., HEIMBACH, Kyle R., MILLER, Brandon S., WATERMAN, Michael T., ZAJACZKOWSKI, Michael T., LUO, Qiang, FULL, Andrew P., KOHLER, Christopher E.
• Granted Patent: US 11,091,675 B2
• Time in Patent Office: Days
• CPC Class Codes: B01J 19/006 Baffles
• CPC Class Codes: B01J 19/0066 Stirrers mixing per se B01F
• CPC Class Codes: B01J 19/085 Electron beams only
• CPC Class Codes: B01J 19/123 Ultraviolet light
• CPC Class Codes: B01J 19/18 Stationary reactors having moving elements inside B01J19/08, B01J19/26 take precedence
• CPC Class Codes: B01J 2219/00094 Jackets
• CPC Class Codes: B01J 2219/00768 vertical
• CPC Class Codes: B01J 2219/00779 Baffles attached to the stirring means
• CPC Class Codes: B01J 2219/08 Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
• CPC Class Codes: C08F 2/01 characterised by special features of the polymerisation apparatus used
• CPC Class Codes: C08F 2/48 by ultraviolet or visible light
• CPC Class Codes: C08F 2/50 with sensitising agents
• CPC Class Codes: C08F 2/54 by X-rays or electrons
• CPC Class Codes: C09J 133/08 Homopolymers or copolymers of acrylic acid esters
• CPC Class Codes: C09J 4/06 Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond in combination with a macromolecular compound other than an unsaturated polymer of groups C09J159/00 - C09J187/00

Abstract

Methods for forming melt processable, actinic radiation polymerizable and crosslinkable adhesives are described. In certain versions, the adhesives or pre-adhesive compositions include two initiators and are polymerized and/or crosslinked by exposure to actinic radiation such as UV light or electron beam radiation. Also described are pre-adhesive compositions including polymerizable monomers, articles including the adhesives, and various methods and systems related to the adhesives and their application. In addition, various apparatuses are described for polymerizing or crosslinking the compositions.

Claims

1. A method of forming an adhesive, the method comprising:

providing a composition comprising at least one monomer, a first actinic radiation initiator, and a second actinic radiation initiator, wherein the second initiator is substantially non-photoactive at activation wavelength(s) of the first initiator;

at least partially polymerizing the composition by exposing the composition to radiation comprising wavelengths corresponding to the activation wavelength(s) of the first initiator;

at least partially crosslinking the composition to thereby form the adhesive by exposing the composition to radiation comprising wavelengths corresponding to the activation wavelength(s) of the second initiator;

wherein at least one of the first and the second initiators is a polymerizable monomer containing a photoinitiator moiety.

2. The method of claim 1 wherein the at least partially polymerizing the composition is performed by irradiating the composition with UV radiation

3. The method of claim 1 wherein the at least partially polymerizing the composition is performed by irradiating the composition with electron beam radiation.

4. The method of claim 1 wherein the at least partially crosslinking the composition is performed by irradiating the composition with UV radiation.

5. The method of claim 1 wherein the at least partially crosslinking the composition is performed by irradiating the composition with electron beam radiation.

6. The method of claim 1 wherein the at least partially polymerizing the composition forms a pre-adhesive composition that comprises controlled architecture polymers comprising a reactive functional group.

7. The method of claim 6 wherein the controlled architecture polymers exhibit an apportionment ratio of the reactive functional group between two blocks of the polymer within a range of from 1.1:

1 to 10,000;

1.

8. The method of claim 1 wherein the composition is free of solvents.

9. An adhesive formed by the method of claim 1.

10. An article comprising the adhesive of claim 9.

11. An acrylate melt processable pre-adhesive composition comprising:

at least one acrylate polymer, the at least one acrylate polymer if formed using actinic radiation polymerization;

an actinic radiation initiator for at least partially crosslinking the polymer, the initiator being a photoinitiator moiety along the polymer backbone, the initiator activatable upon exposure to actinic radiation corresponding to the activation wavelength of the initiator.

12. The composition of claim 11 wherein the pre-adhesive composition prior to activation of the initiator exhibits a viscosity within a range of from 1,000 cps to 80,000 cps at a temperature within a range of from 110°

C. to 180°

C.

13. The composition of claim 11 wherein the pre-adhesive composition exhibits a viscosity within a range of from 30,000 cps to 40,000 cps at a temperature within a range of from 120°

C. to 140°

C.

14. The composition of claim 11 wherein the pre-adhesive composition exhibits a viscosity within a range of from 40,000 cps to 50,000 cps at a temperature within a range of from 120°

C. to 140°

C.

15. The composition of claim 11 wherein the pre-adhesive composition exhibits a viscosity within a range of from 1,000 cps to 15,000 cps at a temperature within a range of from 110°

C. to 130°

C.

16. The composition of claim 11 wherein the pre-adhesive composition comprises at least 95% solids.

17. The composition of claim 11 wherein upon exposure to actinic radiation corresponding to the activation wavelengths of the initiator, the composition forms a pressure sensitive adhesive.

18. The composition of claim 11 wherein the at least one acrylate polymer comprises alkyl acrylate polymers.

19. The composition of claim 11 wherein the acrylate polymer is a controlled architecture polymer comprising a reactive functional group.

20. The composition of claim 19 wherein the controlled architecture polymer exhibits an apportionment ratio of the reactive functional group between two blocks of the polymer within a range of form 1.1:

1 to 10,000;

1.

21. The composition of claim 19 wherein the controlled architecture polymer has a molecular weight within a range of from 10,000 to 300,000.

22. The composition of claim 19 wherein the controlled architecture polymer has a polydispersity value less than 4.0.

23. An article comprising the composition of claim 11.

24. An apparatus for polymerizing and/or crosslinking an adhesive or pre-adhesive composition, the apparatus comprising:

a reaction vessel defining an interior chamber and comprising at least one collar providing access to the interior chamber;

at least one probe assembly supported by the collar, the probe assembly comprising (i) an emitter for emitting light that polymerizes and/or crosslinks the composition, (ii) a light tube extending from the emitter and at least partially disposed within the interior chamber of the reaction vessel, (iii) adjustable positioning provisions for governing position of the light tube within the interior chamber of the reaction vessel, and (iv) a cover disposed at a distal end of the light tube, wherein the cover is transparent or substantially transparent to passage of light emitted from the emitter.

25. The apparatus of claim 24 wherein the probe assembly is positionable to at least one position selected from the group consisting of a surface position, an angled surface position, a sub-surface position, and an angled sub-surface position.

26. The apparatus of claim 24 wherein the apparatus comprises a single probe assembly.

27. The apparatus of claim 24 wherein the apparatus comprises multiple probe assemblies.

28. The apparatus of claim 24 wherein the collar and at least one probe assembly are located along a top wall of the reaction vessel.

29. The apparatus of claim 24 wherein the collar and at least one probe assembly are located along a side wall of the reaction vessel.

30. The apparatus of claim 24 wherein the collar and at least one probe assembly are located along a bottom wall of the reaction vessel.

31. The apparatus of claim 24 wherein the vessel further comprises mixing provisions.

32. An apparatus for polymerizing and/or crosslinking an adhesive or pre-adhesive composition, the apparatus comprising:

a reaction vessel defining an interior chamber and at least one sight glass incorporated in a wall of the vessel and providing visual access to the interior chamber;

at least one probe assembly adjacent the sight glass, the probe assembly comprising an emitter for emitting light that polymerizes and/or crosslinks the composition, the probe assembly positioned such that light emitted from the emitter is directed to the sight glass and passes into the interior chamber of the reaction vessel;

wherein the sight glass is transparent or substantially transparent to passage of light emitted from the emitter.

33. The apparatus of claim 32 wherein the probe assembly further comprises a light tube disposed between the sight glass and the emitter.

34. The apparatus of claim 32 wherein the sight glass is located along a side wall of the reaction vessel.

35. The apparatus of claim 32 wherein the vessel further comprises mixing provisions.

36. An apparatus for polymerizing and/or crosslinking an adhesive or pre-adhesive composition, the apparatus comprising:

a reaction vessel defining an interior chamber, the vessel comprising mixing provisions having at least one blade;

at least one baffle disposed within the interior chamber of the reaction vessel, the baffle comprising at least one emitter for emitting light that polymerizes and/or crosslinks the composition.

37. The apparatus of claim 36 wherein the baffle is a uni-directional light emission baffle having a single face that emits light.

38. The apparatus of claim 37 wherein the baffle is oriented within the interior chamber such that upon operation of the mixing provisions, the at least one blade moves toward the single face of the baffle that emits light.